Teneligliptin which is chemically known as 3-{(2S,4S)-4-[4-(3-methyl-1-phenyl-1H-pyrazol-5-yl)-1-piperazinyl]-2-pyrrolidinylcarbonyl}-1,3-thiazolidine is represented structurally by a compound of formula (I):

U.S. Pat. No. 7,074,794 (US'794) describes the process of preparation of trihydrochloride salt of compound I. The process described in the (US'794) employs diketene for the synthesis of tert-butyl-4-acetoacetylpiperazine-1-carboxylate which is one of the key intermediate in the synthesis of compound I from 1-tert-butyloxycarbonyl piperazine. There are several known drawbacks of the process which includes inter alia the instability of the diketene making it difficult to handle. Unfortunately, few alternatives are available for diketene reaction.
Thus, an object of the present invention is to provide a process to overcome aforesaid problems and to provide simple, cost effective and industrially feasible processes for manufacture of teneligliptin and pharmaceutically acceptable salt or solvate thereof. Teneligliptin and pharmaceutically acceptable salt or solvate thereof prepared by the process of present invention provides both enhanced yield and purity.